06H905601A Spark plug problem

[56OctyVRS]

Has anyone else had problems with these spark plugs?  I ask because I purchased a set two months ago and recently had problems with WOT. They have only covered about 2-3000miles and would misfire under WOT and generally run rough, but on part throttle it was fine.  I knew it wasnt the coil packs as I had them replaced under the recall in April. I refitted my old Bosch spark plugs and took the car for a spin, works perfect!  I am taking the new plugs back to the garage for an exchange but was wondering if anyone else has had this problem?

Cheers Matt

[Hurdy]

Not heard of any issues with this plug, but just for clarity this plug is an NGK PFR7S8EG.

[56OctyVRS]

Just been to TPS and they say because its a plug and electrical it wil need to a diagnostic report to prove its faulty. I said I would refit the plugs in front of them and go on a test drive to prove it.  But he said they need a diagnostic report done by a Skoda garage and that Skoda would change the parts.  I am a little sceptical that a Skoda garage would change OE parts not bought from them.  I will phone Skoda and find out what their stance is?